Recently, due to factors such as traffic environments or local climates, these has been a trend for rapid increases in transportation (logistics) costs. Particularly, since the amount of (significantly) heavy cargo that can be carried by a single transportation system (vehicle) is limited, heavy cargo incurs much higher transportation costs. In addition, significantly heavy cargo nub many limitations when being moved between production lines in a factory.
For example, it takes considerable time and costs to transport significantly heavy products from an iron mill such as plate-shaped slabs or steel sheets (particularly, thick plate products) within an iron mill itself or to ship such significantly heavy products for long-distance transportation.
Although products such as slabs are commonly carried between production lines in a factory within a relatively short distance, thick plate products are often transported using ship-based transportation (logistics) systems due to the sizes (weights) thereof.
For example, FIG. 1 illustrates a transportation system 300 (i.e., a shipping system) constructed using an existing transportation vehicle (i.e., an elevator type transporter of the related art).
As illustrated in FIG. 1, generally, a thick plate product 310 located in a yard is lifted onto a heavy iron pallet 350 by using a crane 320 and a lifting apparatus 330 (such as an electromagnetic block), and the pallet 350 on which the thick plate product 310 is disposed is carried to a ship 360 using an elevator type transporter 340.
Thereafter, the pallet 350 on which the thick plate product 310 is disposed is transported onto the ship 360, and only the elevator type transporter 340 returns to the yard for repeating the shipment of thick plate products 310.
As described above, a thick plate product is loaded on a ship together with a pallet on which the thick plate product is disposed, because it is difficult and cumbersome to move the thick plate product from the pallet to the ship using equipment, and the pallet is commonly reused when the thick plate product is unloaded from the ship after transportation.
Korean Patent Application Laid-open Publication No. 2002-0016020 discloses a pallet-related technique, and Korean Patent Registration No. 10-0955020 discloses an apparatus for lifting and unloading a significantly heavy object such as a slab similar to a thick plate product.
That is, as disclosed in the patent application and the registered patent, large equipment is necessary to lift a slab or thick plate (product) onto a transportation apparatus and unload the slab or thick plate product from the transportation apparatus, in addition to the necessity of a pallet for disposing the slab or thick plate product thereon. Particularly, since such a pallet is a heavy iron-component assembly weighing twenty tons or more, the manufacturing cost thereof is high.
Therefore, the above-described transportation system 300 for transporting thick plate products by using a pallet and an elevator type transporter of the related art has the following problems.
First, according to a method of the related art, additional equipment is used to lift and unload a thick plate product, and a pallet is used to accommodate a thick plate product thereon during transportation, thereby incurring additional costs for manufacturing and managing such additional equipment. Particularly, transportation (distribution) work may be retarded due to lifting and unloading operations, and the amount of cargo that can be shipped in a given period of time may be limited, thereby markedly increasing overall transportation (logistics) costs.
Secondly, a thick plate product is loaded on a ship together with a pallet used to accommodate the thick plate product thereon as illustrated in FIG. 1, and the pallet is reused when the thick plate product is unloaded from the ship. However, since such a pallet is relatively large and heavy, as described in the patent application, the available cargo space in a ship is consequently reduced, and since the pallet is transported as cargo, shipping costs are increased. That is, time and costs are wasted.
Thirdly, since a significantly heavy object handling operation is performed to lift such a thick plate product on a pallet or to unload the thick plate product from the pallet, accidents such as a heavy object falls, or accidents related to worker safety are likely to occur.
That is, transportation systems for transporting (shipping) thick plates (thick plate products) by a method using existing devices such as the pallet 350 and the elevator type transporter 340 illustrated in FIG. 1 have many problems.
In addition, since such a pallet and an elevator type transporter are used to carry slabs as well as thick plate products, problems similar to the above-described problems may be caused.